Velopharyngeal Structure and Function This proposal consists of studies of the anatomy and physiology of the velopharyngeal mechanism. A primary concern will be with velopharyngeal function during speech production. Relationships between velopharyngeal function and laryngeal function will also be investigated. Studies are planned in two main areas. We have past and present research efforts dealing with gross morphology of the velum. In this project that anatomical work is expanded to the histological level. We also have- developed a conceptual model of the role of articulatory function during speech. This model is combined with general notions of motor control to investigate function of the velopharyngeal mechanism during speech. Data gathered within such a framework will provide a better understanding of the normal mechanism. Such understanding will guide our efforts to rehabilitate those with abnormal mechanisms. The central thrust of the first series of studies involves analyses of the kinematic properties of the velopharyngeal mechanism during speech production. Measures of movement timing, velocities and displacements will be related to electromyographic recordings from the velopharyngeal musculature, and compared to general principles of movement dynamics derived from study of other body structures. Velopharyngeal function will also be related to movement properties of other articulators, especially the larynx. The second series of studies is designed to broaden our understanding of the histology of the velopharyngeal region. These studies are aimed at a description of the histology of various regions of the velopharynx, including a description of nerve fiber pathways, motor endplates, and sensory receptors, and should compliment our ongoing efforts.